Study On Genetic Diversity And Photosynthetic Performance Of Mungbean Varieties Released In Jilin Province

Mungbean(Vigna radiate) is one of the main cultigen among subgenus Ceratotropis genus Vigna, and play a particular role in people’s lives. Mungbean cultivated long time ago is tranditional export agricultural product in China, and it is a popular crop with both nutrient including rich portein, vitamin, and mineral elements and medicinal value.Mungbean is planted widely in Jilin province, especially in Baicheng city(Taonan county-level city, Tongyu city, and Zhenlai county) and Songyuan city(Qianguo county, Qianan county, and Changling county). Nowadays, mungbean breeding units in Jilin province have bred a few varieties with good traits which played an import role in production. In order to confirm the new breeding goal, we researched the change of main agoromic characters of mungbean varieties released in recent years, the change of organs dry matter and partial photosynthetic performance of high, intermediate, and low yield varieties at R2stage, R4stage, and R6stage, and the diversity based on agoromic characters of mungbean varieties released in Jilin province, we also researched the influence of plant density with Jilu3. Moreover, we researched the early identification method of drought-tolerance of mungbean cultivars. The main results are as follows:1、16morphological traits of21mungbean varieties released in Jilin province were analysed, the results showed that the growth habit, pod color, and seed color were monomorphic. The Shannon-Weaver’s information index of yield per plant and pod shape was the highest and lowest, respectively. All mungbean varieties were clustered into6groups. The relationship among all mungbean varieties was closer, so the diversity of parents should be increased in order to improve the population structure of mungbean varieties.2、A method for identifying drought-tolerance of mungbean varieties was discussed in order to provide a theoretical basis for drought-tolerance breeding of mungbean. A simple method of germination rate at24h-after-water-absorption was used and verified to investigate mungbean drought-tolerance. The drought-tolerance of25mungbean germplasms were graded according to seed germination rate at the germination stage, and then in pot water-control trails at vegetative growth stage and reproductive growth stage. It indicated that there were significant differences in drought-tolerance among mungbean materials. Water absorption made no difference to drought-tolerance. However, seedling branch root number and main root length had significant positive correlation with drought-tolerance, and root dry weight had positive correlation with drought-tolerance. Under repeated stress of supplying water for24h after germination and then no water for24h, the survival rate of drought-tolerant cultivars was higher than those of ordinary ones. At the vegetative growth stage, temporary wilting(under soil moisture of9%to11%)treatment led to leaf wilting of ordinary cultivars, with reduced plant height, stem diameter and leaf area. Among the traits, the changes of stem diameter and leaf area were highly significant. During the reproductive growth stage, temporary wilting led to significantly lower root biomass and branch biomass in ordinary cultivars. When moved to the seed filling stage, ordinary cultivars wilted without recovery. On the contrary, the drought-tolerant cultivars still maintained ability to grow. These results indicated that24h-germination-rate of mungbean seeds could be used as a method in drought resistance identification and screening. They also showed that mungbean plants at seed filling stage were most sensitive to water stress.3、We researched the change of yield and other main agronomic characters with23mungbean varieties released from1986to2011in Jilin province. The yield increased22.99%from1986to2011during the mungbean variety improvement in Jilin province. Number of pods per plant, number of seeds per pod, and yield per plant increased significantly, which indicated the storage capacity of new varieties had enlarged as the released year went. There was a positive correlation between yield and number of pods per plant, number of seeds per pod, yield per plant, and pod length. Especially, there was an extremely significant positive correlation between yield and number of pods per plant, which indicated number of pods per plant was the main factor influencing mungbean yield. Both leaf blade length and leaf blade width did not change significantly, but there was a significant positive correlation between leaf blade width and yield. Plant height, node number of main stem, and number of branches decreased significantly, ang there was a significant negative correlation between yield and plant height and node number of main stem. The results showed that the source of mungbean variety did not change significantly during the variety improvement. So the key of high yield breeding goal was to increase source and enlarge storage capacity, we should select the new variety with more pods, long pod and large seed. Meanwhile, we should pay attention to improve the plant type.4、In order to confirm the influence of plant density to yield and other characters, the field experiment was carried out under five levels of plant density(10.5×104 plants/hm2,11.8×104plants/hm2,13.8×104plants/hm2,16.7×104plants/hm2,20×104plants/hm2) in both2007and2008. Plant height, node number of main stem, and yield were not significantly different under different plant densities in both year,100-seed weight had extremely significant diffenrence and significant diffenrence in2007and2008, expectively. Number of branches, number of pods per plant, and yield had extremely significant diffenrence or significant diffenrence in both years. The yield was the highest at16.7×104plants/hm2in2007, and13.8×104plants/hm2in2008, which showed Jilu3could get high yield at middle-high plant density. Path analysis showed that the direct factors which had great influence to yield were different at different plant density, so we should choose a right plant density based on variety’s characters to improve mungbean yield.5、We researched the change of partial photosynthetic performance and organs dry matter, also discussed the relationship between yiled and partial photosynthetic performance and organs dry matter of high, intermediate, and low yield varieties at R2stage, R4stage, and R6stage.(1)The photosynthetic rate of high, intermediate yield varieties decreased at R4stage, increased at R6stage. The photosynthetic rate of low yield varieties decreased by6.93%at R6stage. There was no significant difference in photosynthetic rate of three kinds of yield varieties at R2, R4stage, but photosynthetic rate of high yield varieties were extremely significant higher than low yield varieties, and photosynthetic rate of intermediate yield varieties were significant higher than low yield varieties at R6stage. There were extremely significant positive correlation and significant positive correlation between yield and photosynthetic rate at R2, R6expectively.However, there was no significant positive correlation at R4stage.(2)The trend of total dry matter change of different yield varieties was all higher first, lower second at three growth stage. At R4stage, root dry matter decreased greatly by50-54%, stem dry matter increased greatly by75%-107%, leaf dry matter increased by18%-30%. At R6stage, both stem dry matter and leaf dry matter decreased greatly by31%-41%,4%-28%, expectively. And pod dry matter increased greatly by36%-47%. The pod dry matter of high yield varieties increased by46.92%, and the pod dry matter of intermediate, low yield varieties increased by36.48%,38.35%, expectively.(3)At R2stage, stem dry matter had closely positive direct and indirect influence on mungbean yield(P=0.61781, r=0.734), and petiole dry matter had negtive direct and indirec influence on yield(P=-0.35515). At R4stage, leaf dry matter had closely positive direct and indirect influence on mungbean yield(P=0.41421, r=0.371), and stem dry matter had negtive direct and indirec influence on yield(P=-0.15817). At R6stage, pod dry matter had closely positive direct and indirect influence on mungbean yield(P=0.31494, r=0.518), and petiole dry matter had negtive direct influence on yield(P=-0.12406). Therefore, it was the accumulation and distribution of the dry matter to form grain yield of mungbean. The more the dry matter distributed to the grain, the higher the yield was.